1. Field
One embodiment of the present invention relates to a magnetic recording media of the discrete track type and a magnetic recording device.
2. Description of the Related Art
Recently, in improving the track density of a hard disk drive (HDD), a problem of interference between adjacent tracks has become obvious. Especially, it is an important technical problem to reduce blur in writing operation due to the fringe effect of a write head magnetic field. A discrete track recording media (DTR media), which has its recording tracks physically separated, can reduce the side-erase phenomenon at the time of writing operation, side-read phenomenon in which information of adjacent tracks is mixed up at the time of reading operation, etc. Consequently, it is possible to greatly improve the track density. Accordingly, a magnetic recording media with high density can be provided.
On the other hand, in the conventional DTR media, since a servo signal is formed depending on absence or presence of magnetic recording layer, the servo signal intensity of the conventional DTR media is half that of a normal magnetic recording media having a continuous film, undesirably. The reason is as follows. In case servo writing is performed on a normal magnetic recording media having a magnetic recording layer being a continuous film, a servo signal is formed by upward magnetization (+1) and downward magnetization (−1). On the other hand, as for the conventional DTR media on which recesses are formed by completely etching a magnetic recording layer in the servo area, a servo signal is formed by magnetization (+1) and no magnetization (0). Accordingly, in principle, the servo signal intensity of the conventional DTR media is half that of a normal magnetic recording media having a continuous film. Thus anticipated reduction in signal intensity due to processing as well as reduction in servo signal-to-noise ratio (SNR) in principle is a crucial weak point for a drive having a DTR media loaded thereon.
In Jpn. Pat. Appln. KOKAI Publication No. 2000-306227, there is disclosed a magnetic recording media in which the depth of magnetic recording layer in the data area is different from that of magnetic recording layer in the servo area. However, in the magnetic recording media, the magnetic recording layer is completely separated by non-magnetic material in the servo area, and improvement of the servo SNR is not taken into consideration.